The present invention pertains to an implantable device and method for adjustably restricting a body lumen such as the urethra by placing an expandable element having the form of a membrane or balloon adjacent to the body lumen. The invention also includes a device assembly and method for expansion of the expandable membrane element to cause displacement of the body tissue adjacent to the body lumen so as to adjustably restrict or coapt (close) the lumen. Expansion of the membrane element is accomplished by delivering a fluid material into a rear port of the implantable device remote from the expandable element but near the patient's skin, thus enabling post-operative adjustment with minimal surgical invasiveness.
Several devices for body lumen restriction to treat urinary incontinence are known and disclosed in the prior art, and have employed various means such as an outer tube for delivery of a detachable expandable membrane into body tissue. However, the known prior art devices do not provide any post-operative adjustability feature for introduction of new material into the expandable element to change the degree of restriction of a body lumen. These prior art devices have also proven to be of risk to the patient with respect to infection or migration back along the tract by which they were introduced through the body tissue. Such migration of the implantable device would render the treatment of incontinence ineffective and the device may even erode into the urinary tract causing infection and other severe complications.
For example, U.S. Pat. No. 4,733,393 to Haber et al discloses a hypodermically implantable genitourinary prosthesis which provides a extensible, inflatable tissue expanding membrane to be located in proximal urethral tissues to add bulk to these tissues for overcoming urinary incontinence by localized increase in tissue volume. But the prosthesis does not include any means for post-operative adjustments. U.S. Pat. No. 4,802,479 to Haber et al discloses an instrument for dispensing and delivering material in an inflatable membrane for purposes of a genitourinary prosthesis within the tissues of a patient for overcoming urinary incontinence. However, the inflatable membrane isolated within the tissues is not attached to a conduit and a rear filling means provided immediately below the patient's skin for post operative adjustment or titration of restriction of the urethral lumen. U.S. Pat. No. 4,832,680 to Haber et al discloses an apparatus for hypodermically implanting a genitourinary prosthesis comprising an extensible containment membrane for retaining a fluid or particulate matter which is injected from an external source. But again the distensible membrane is isolated within the patients body tissues and is not connected to a conduit and rear port close to the surface of the skin for post-operative adjustment. Moreover, in an unadjustable device the patient is at risk for retention; where urine cannot be passed because the membrane was initially filled too much causing over restriction of the urethra. Such a condition could lead to kidney damage which would require major corrective surgery or at minimum use of self-catheterization to empty the bladder on a regular basis thus increasing the risk of urinary tract infection (UTI).
U.S. Pat. No. 5,304,123 to Atala et al discloses a detachable membrane catheter incorporated into an endoscopic instrument for implantation into the suburethral region of a patient. Also, U.S. Pat. No. 5,411,475 to Atala et al disclose a directly visualized method for deploying a detachable membrane at a target site in vivo.
In all of these prior art devices, the expandable membrane is delivered to the desired location through an outer tube means. The absences of this requirement in the present invention allows the device to be smaller in diameter, thus allowing it to be delivered through a smaller less traumatic surgical tract.
Also, the present invention utilizes an expandable element attached remotely to a conduit to facilitate delivery or removal of fluid from the expandable element via a rear port which is in close proximity to the patient's skin.
In the present invention, the presence of the port located near the surface of the patient's skin affords the additional advantage of allowing the device to be easily removed through a small incision in the skin if, for instance, it was to become infected or malfunction, whereas all the prior art devices would require major surgery. Furthermore, the presence of the conduit and rear port left in the device delivery tract will serve to prevent backward migration of the expandable element along the tract, a problem which has been noted with prior art devices.
Ideally, if a patient's situation at some future time requires a desirable addition or removal of material to or from the expandable membrane to adjust the restriction and provide a resultant greater/lesser pressure and resistance on the urethra, it is desirable if material could be conveniently adjusted in the membrane. Therefore, the intent of the present invention is to allow a more normal voiding process while maintaining continence in the patient. This post-operative adjustment feature promotes normal voiding patterns for the patient, and appropriate vesicourethral pressure during voiding.
Post-operative adjustment could be done in a semi vertical or horizontal position with the bladder full after anesthesia is resolved and edema is minimal. Adjustment of the expandable element could be done by palpating the rear port which contains a septum for either filling or removing fluid to further titrate the volume of the expandable membrane. This will allow more natural voiding while maintaining continence for the patient.
Because the prior art has not disclosed the components of the present invention, if a physician were to undertake subsequent membrane size adjustments with the prior art devices the following steps would need to be accomplished to make the expandable membrane adjustable post-operatively:
(a) in vivo visualization of the membrane and delivery of a needle deep into the tissue site where the membrane implant resides;
(b) access the inside of the membrane by puncturing it to add or remove material from the membrane, so as to increase or decrease patient urethral restriction; and
(c) sealing the membrane so that subsequent loss of fluid does not occur.
Thus, an important medical need exists for an improved implantable device having an expandable membrane element that incorporates a permanently attached conduit and rear port which can be accurately delivered adjacent to a desired body lumen site in a patient, and to which suitable fluid material can be conveniently and reliably added or removed as required.
The primary purpose of the invention is to provide an adjustable implantable device which will restrict urine from involuntarily escaping from the bladder, thus establishing continence for the patient. This adjustable component can be done in a post-operative manner once the patient has resume daily activity via an evaluation to determine what activities cause bladder stress and observable incontinence.